Leaded integrated circuit (IC) or chip carriers have come into common use to provide a means of physically and electrically coupling integrated circuits to a surface such as printed circuit boards (PCBs) or substrates. The fine wire leads of such carriers are typically spaced very closely and are therefore examples of fine pitch leaded components. The close spacing of the leads create problems in soldering the leads to the printed wires of the PCB or substrate without inadvertently breaking the leads or displacing the leads.
Current manufacturing practices in handling fine pitch leaded chip carriers utilize one of two processes to cut and form the leads prior to placement of the device. One method is to cut and form at the chip packager's site then transport the devices in trays. The parts are then picked and placed from the trays using a robot or a functional equivalent. The second method is to deliver the parts from the chip packager's site for use in a tape pack form where a retaining ring or frame is still in place. Conventionally, the ring is sheared and the leads are formed at the assembly site where the chip carrier is to be mounted on the PCB or substrate. The device or chip carrier is then placed and reflowed on site without the ring. The problem with the current methods is that there is a potential for lead damage to occur from handling prior to the parts being placed and soldered. This damage potential is due to the loss of rigidity in the leads that the retaining ring provides.
It would therefore represent an advance in the art to provide a means for reliably retaining the ring of the chip carrier throughout the entire soldering process to prevent lead damage.